1. Field of the Invention
The invention relates generally to configurable data processing devices running an upgradable program or microcode the configuration of which requires at least some mandatory parameters, and relates particularly to a method of upgrading a program using associated configuration data.
2. Description of the Related Art
Configurable network devices have generally a lot of configuration parameters. For a network device to perform a task, some parameters can use factory default values but other ones cannot. The parameters which can keep factory default values are called optional parameters. The parameters that cannot keep factory default values are called mandatory parameters.
When connecting such a device for the first time to the network, the user has to configure these mandatory parameters and can also perform more fine-tuning of the device by changing the values of the optional parameters. Once this operation is completed, the device is operational and its configuration parameters are saved as a configuration file in a permanent memory such as an NVRAM.
During the device life, the microcode development engineering of the device perform function enhancement and bug fixes of the microcode when necessary. These bug fixes and function enhancement are grouped in a new microcode version having a number n+1whereas the most recent version of the microcode has a number n. Because of the new functions, the format of the configuration file may change because it contains new record sizes, new values, or new entries.
Each program version can be installed by the user following upgrading instructions. When the user wants to change, inside the device, the microcode version n by a microcode version n+1, for a safety reason he expects to be able to easily return to microcode version n in case of failure of the device when running microcode version n+1. This is generally made by storing version n+1 into an alternate location. Once version n+1 is activated, the location where version n is stored becomes the alternate location for a future upgrade of the program with a version n+2. Doing so, there are always two versions of the microcode inside the device. So, a command called SWAP MICROCODE can be provided to activate any one of these microcode versions.
When changing version n by version n+1, the user also expects not to have to re-enter all the device configuration parameters before its device becomes operational again. When version n+1 is first activated after version n, version n+1 finds the- configuration file that version n has saved in memory. Microcode version n+1 being more recent than the previously running microcode version n, the software development engineering may implement the translation function for version n+1 to be able to understand the configuration file associated with version n. During such a translation, record sizes are re-computed, old values are translated into new values and new entries are initialized with values that allow the device to operate anyway. Once translated, the configuration file is stored into memory as a new configuration file associated with microcode version n+1. The device probably operates properly and the user can take benefits of the new functions and bug fixes.
But, if the user experiences troubles in the device operation with the microcode version n+1, he may want to re-activate microcode version n. Doing so, the newly activated microcode version n finds in the memory a configuration file formatted and stored by a more recent version. In other words, the microcode finds record sizes, values, and entries that did not exist at the time version n was implemented by development engineering. So, microcode has no other choice than retrieving factory default parameters. But, as mandatory parameters are no longer set, the device is no longer operational.
Two methods can be used to solve the above problem. The first method consists in saving the configuration file associated with version n onto a diskette on a hard disk. Unfortunately, diskette or hard disk drives are not always present on devices used in a network because of failure rates. The second method consists in retrieving the configuration file from a server onto which the user has previously uploaded it before activating version n+1. But this requires a configuration of mandatory parameters for the device to be able to reach the network server prior to downloading the configuration file.
Accordingly, the object of the invention is to achieve a method of upgrading a program wherein the configuration data associated with the previous version of the microcode are automatically stored when this previous version is replaced by a new version.
The invention relates, therefore, to a method of upgrading a program used in any data processing device having a permanent memory, in particular a network device, from a version n to a version n+1, wherein, at any time, both the recent version and the previous version of the program are stored in a first and a second location of the memory, each one of version n and version n+1 using, respectively, configuration data of format n or format n+1when used as the current version, and the configuration data of format n being automatically stored into the memory while the version n+1 of the program is stored into the second location of the memory.